Unit testing with Jest

I’ve been working on developing the classic game of Battleship in plain JavaScript. Part of the assignment (which you can read about here) is using Test-Driven Development (TDD) as a tool to write the code.

☝️ Write a test, write the code to pass the test.

The tests are meant to check whether functions are working correctly. For example, if I have a test like this:

test("attack is a miss", () => {
  playerOneGameboard.receiveAttack("A1");
  expect(playerOneGameboard.array[0].missedShot).toBe(true);
});

I can see if my code is working properly, without using console.log.

The benefits of TDD are many, but the ones I’ve noticed the most in my own code are (1) improving design (tightly coupled vs loosely coupled!) and (2) encouraging refactoring. Plus, it’s been (3) fun to write these simple tests and then make them pass.

And with a game like Battleship, there are many conditionals, and thus, many tests!